The application of biomaterials science to devices now in development would benefit from the availability of well-characterized polymers with step wise variable surface composition. Control of surface chemistry bulk composition has utility in tissue engineering, in fabrication of conventional medial devices and in new nanotechnology application of polymers. In Phase we confirmed that, while rates are slower, equilibrium surface tension/composition of polymer blends is quantitatively similar to conventional surfactants in liquid Solvents. Energy minimization drives surface equilibration, which depends on the nature of the interface, e.g., air vs. blood. Phase II involves preparation of three series of polymer blends with varying surface composition, each with a different surface modifying end group: silicone, fluorocarbon, polyethyleneoxide. Each series will be characterized by several surface-sensitive methods including Sum Frequency Generation Spectroscopy, XPS, AFM and surface tension/wettability. Each characterized series will be subjected to a battery of short-term in vitro biological tests including (competitive) protein adsorption and complement activation. The hypothesis to be testes is that biological response will vary monotonically with surface chemistry when the surface chemistry is determined by truly surface-sensitive methods and knowledge of the kinetics of polymer surface rearrangement following upon immersion of air-equilibrated surfaces into aqueous fluids.
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